# Important Questions for CBSE Class 6 Maths Chapter 5 – Understanding Elementary Shapes

## Important Questions Class 6 Maths Chapter 5 – Understanding Elementary Shapes

Maths is a major subject that is taught in school. You may wonder why we study Maths in school. This subject has great applicability in our life. Maths is needed everywhere, from daily accounting to large-scale constructions to space science.

## Understanding Elementary Shapes Class 6 Important Questions

In this chapter, you will learn how to measure a line and an angle, different types of angles, clock and anti-clock and faces, edges and vertices of a three-dimensional object. This chapter is very important, and students must practise questions regularly to score better in exams.

Extramarks is a leading company that provides important study material to students. Our experts have prepared the Important Questions Class 6 Maths Chapter 5 to help students solve questions. They have collected questions from different sources such as textbook exercises, CBSE sample papers and CBSE past years’ question papers. They have also provided the solutions in this question series.

Extramarks provided a wide range of study material to students. You will find the CBSE syllabus, CBSE past years’ question papers, CBSE sample papers, CBSE revision notes, CBSE extra questions, NCERT syllabus, NCERT exemplar, NCERT solutions, NCERT solutions, important questions, vital formulas and many more. You may register on our official website to download these resources of study material.

## Get Access to CBSE Class 6 Maths Important Questions with Solutions

Also, get access to CBSE Class 6 Maths Important Questions for other chapters too:

### CBSE Important Questions for Class 6 Maths

Sr No Chapter No Chapter Name
1 Chapter 1 Knowing Our Numbers
2 Chapter 2 Whole Numbers
3 Chapter 3 Playing with Numbers
4 Chapter 4 Basic Geometrical Ideas
5 Chapter 5 Understanding Elementary Shapes
6 Chapter 6 Integers
7 Chapter 7 Fractions
8 Chapter 8 Decimals
9 Chapter 9 Data Handling
10 Chapter 10 Mensuration
11 Chapter 11 Algebra
12 Chapter 12 Ratio and Proportion
13 Chapter 13 Symmetry
14 Chapter 14 Practical Geometry

## Understanding Elementary Shapes Class 6 Extra Questions with Solutions

Subject experts at Extramarks have collated these questions from several sources. They have taken help from the textbook syllabus, CBSE sample papers and NCERT exemplar. They have also included a few questions from past years’ question papers so that students may have ideas about possible exam questions. They have included the solutions to the questions in the Important Questions Class 6 Maths Chapter 5. Experienced professionals have further checked the answers to ensure the best content quality. The questions are-

Question 1. What is the measure of – (i) a right angle? (ii) a straight angle?

(i) The exact measure of a right angle is 90°.

(ii) The exact measure of a straight angle is 180°.

Question 2.

Draw a rough sketch of the following:

(a) Acute angle

(b) Obtuse angle

(c) Reflex angle

(a) Acute angle

(b) Obtuse angle

(c) Reflex angle

Question 3. Classify each one of the following given angles as right, straight, acute, obtuse or reflex:

(a) Acute angle – as its measure is less than 90º.

(b) Obtuse angle – as its measure is more than 90º but less than 180º.

(c) Right angle – as its measure is 90º.

(d) Reflex angle – as its measure is more than 180º but less than 360º.

(e) Straight angle – as its measure is 180º.

(f) Acute angle – as its measure is less than 90º.

Question 4. What is the main disadvantage of comparing line segments by just mere observation?

By mere observation, we cannot be sure about our judgement. When we have to compare two line segments of almost the same length, we cannot be certain which is the line segment of greater length. Hence, it is not an appropriate method to compare the line segments having a slight difference in their lengths. This is the disadvantage of comparing line segments by mere observation.

Question 5. Why is it a good choice to use a divider rather than a ruler while measuring the length of a line segment?

It is a better choice to use a divider rather than a ruler because while using a ruler, positioning errors may happen due to the incorrect positioning of the eye.

Question 6. Draw any line segment, say AB. Now, take any point C between A and B. Measure the lengths of – AB, BC and AC. Is AB = AC + CB?

Since it is given that point C lies between A and B. Hence, all points lie on the same line segment

1. Therefore, for each and every situation at which point C is lying between A and B, we may say that.

AB = AC + CB

For example:

AB is a line segment of 7 cm, and C is a point which is between A and B so that AC = 3 cm and CB = 4 cm.

Hence, AC + CB = 7 cm

Since, AB = 7 cm

∴ AB = AC + CB is verified.

Question 7. If A, B, and C are three points that are present on a line so that AB = 5 cm, BC is equal to 3 cm and AC is equal to 8 cm, which one of these lies between the other two?

Given that AB = 5 cms

BC = 3 cms

AC = 8 cms

Now, it is clear that we have AC = AB + BC,

Therefore, point B lies between A and C.

Question 8. Draw any five triangles and measure their sides. Check in each and every case if the sum of the length of any two sides is always less than the third side.

We will be using the concept knowledge of triangles to solve this.

Case I. In ∆ABC

Consider that AB = 2.5 cms, BC = 4.8 cms and AC = 5.2 cms

AB + BC = 2.5 cms + 4.8 cms = 7.3 cm

As we know, 7.3 > 5.2 and  AB + BC > AC

Hence, the sum of any of the two sides of the triangle is greater than the third side.

Case II. In ∆PQR,
Consider that PQ = 2 cms, QR = 2.5 cms and PR = 3.5 cms

PQ + QR = 2 cms + 2.5 cms = 4.5 cms

As we know, 4.5 > 3.5, PQ + QR > PR

Hence, the sum of any of the two sides of the triangle is greater than the third triangle side.

Case III. In ∆XYZ,

Consider that XY = 5 cms, YZ = 3 cms and ZX = 6.8 cm

XY + YZ = 5 cm + 3 cm = 8 cm

As, we know 8 > 6.8 and XY + YZ > ZX

Hence, the sum of any of the two sides of a triangle is greater than the third side.

Case IV. In ∆MNS,

Consider that MN = 2.7 cm, NS = 4 cm and MS = 4.7 cm

MN + NS = 2.7 cm + 4 cm = 6.7 cm

As we know, 6.7 >4.7 and MN + NS > MS

Hence, the sum of any of the two sides of a triangle is greater than the third side.

Case V. In ∆KLM,

Consider that KL = 3.5 cm, LM = 3.5 cm and KM = 3.5 cm

KL + LM = 3.5 cm + 3.5 cm = 7 cm

Since we know 7 cm > 3.5 cm and KL + LM > KM

Hence, the sum of any of the two sides of a triangle is greater than the third side. Hence, we will conclude that the sum of any two sides of a triangle is never less than the third side.

Question 9.

Write down the measures of

(a) some acute angles

(b) some obtuse angles

(a) 25°, 63° and 72° are acute angles.

(b) 105°, 120° and 135° are obtuse angles.

Question 10.

State true(T) or false(F):

(a) The measure of an acute angle is < 90°.

(b) The measure of an obtuse angle is < 90°.

(c) The measure of a reflex angle is > 180°.

(d) The measure of one complete revolution is equal to 360°.

(e) If m ∠A = 53° and ∠B = 35°, then is m∠A > m∠B.

(a) True

(b) False

(c) True

(d) True

(e) True

Question 11.

How many right angles will you make if you start facing

(a) South(S) and turn clockwise to the West(W)?

(b) North(N) and turn anti-clockwise to the East(E)?

(c) West(W) and turn to West(W)?

(d) South(S) and turn to the North(N)?

Suppose we revolve one complete round in either a clockwise or anti-clockwise direction. In that case, we will revolve by 360º or four right angles, and the two adjacent directions will be at 90º or one right angle away from each other.

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(a) Now, if we start facing South and turn clockwise to West, we make one right angle (90 degrees).

(b) If we start facing North(N) and turn anti-clockwise to East(E), we make three right angles (90 degrees).

(c) If we start facing West(W) and turn to West(W), then we make one complete round or four right angles (90 degrees).

(d) If we start facing South(S) and turn to North(N), then we make two right angles (90 degrees).

Question 12.

Complete each of the following statements so as to make a true statement –

(i) A _______ is a rectangle with a pair of adjacent sides equal.

(ii) A parallelogram with a pair of adjacent sides equal is called a _______.

(iii) A quadrilateral having exactly one pair of parallel sides is called a _______.

(iv) A quadrilateral having both pairs of opposite sides parallel is called a _______.

(v) A parallelogram whose each angle is a right angle is called a _______.

(i) square

(ii) rhombus

(iii) trapezium

(iv) parallelogram

(v) rectangle.

Question 13.

A figure is regular if its all sides are equal in length and all angles are equal in measure. Can you identify a regular quadrilateral?

In a square, for example, all the interior angles are 90°, and all the sides are of the same length. Therefore, a square is a regular quadrilateral.

Question 14.

Fill in the blanks with – acute, obtuse, right or straight angle:

(i) An angle whose measure is less than that of a right angle is ______

(ii) An angle whose measure is greater than that of a right angle is ______

(iii) An angle whose measure is the sum of the measures of two right angles is ______

(iv) When the sum of the measures of two angles is that of a right angle, then each one of them is ______

(v) When the sum of the measures of the two angles of that of a straight angle, and if one of them is an acute angle, then the other angle should be ______

(i) acute

(ii) obtuse

(iii) straight

(iv) acute

(ii) obtuse

Question 15.

Which of the following are the models for perpendicular lines?

(a) The adjacent edges of a tabletop

(b) The lines of a railway track

(c) The line segments form the letter ‘L’

(d) The letter V

(a) Yes, the adjacent edges of a tabletop are the models of perpendicular lines.

(b) No, the lines of railway tracks are parallel to each other. So they are not the model for perpendicular lines.

(c) Yes, the two line segments of ‘L’ are a model for perpendicular lines.

(d) No, the two line segments of the letter ‘V’ are not the model for perpendicular lines.

Question 16.

Name the types of the following triangles –

(i) Triangle with lengths of the sides 7 cm, 8 cm and 9 cm.

(ii) Triangle ABC with sides AB = 8.7 cm, AC = 7 cm and BC = 6 cm.

(iii) Triangle PQR such that side PQ = QR = PR = 5 cm.

(iv) Triangle DEF with m∠D = 90°

(v) Triangle XYZ with m∠Y = 90° and XY = YZ.

(vi) Triangle ∆LMN with m∠L = 30° m∠M = 70° and m∠N = 80°.

(i) Lengths of the sides of the triangle are given as 7 cm, 8 cm and 9 cm.

Since all the given sides of the given triangle are different.

Hence, it is a Scalene triangle.

(ii) Given that: AB = 8.7 cm, AC = 7 cm and BC = 6 cm

Here AB ≠ AC ≠ BC Hence, ∆ABC is the Scalene triangle.

(iii) Given that: PQ = QR = PR = 5 cm

Since all sides are equal.

Hence, it is an equilateral triangle.

(iv) Given that: In ∆DEF, m∠D = 90°

Hence it is a right-angled triangle.

(v) Given that: In ∆XYZ, m∠Y = 90° and XY = YZ

Hence it is a right-angled triangle.

(vi) Given that: ∆LMN, m∠L = 30°, m ∠M = 70° and m∠N = 80°.

Hence it is an acute-angled triangle.

Question 17.

Examine whether the following figures are polygons. If anyone among them is not a polygon, give the reason why.

</spa

(a) It is not a polygon because it is not a closed figure.

(b) Yes, it is a polygon as it is made of 6 sides.

(c) No, it is not made of any line segments.

(d) No, it is not made only from line segments.

Question 18.

A diagonal is a line segment that will join any of the two vertices of the polygon and is not any side of the polygon. Draw a sketch of a pentagon and also draw its diagonals.

It can be observed from the question that AC, AD, BD, BE, and CE are the diagonals.
Question 19.

State true(T) or false(F) –

(i) Each angle of the rectangle is a right angle.

(ii) The opposite sides of a rectangle are always equal in length.

(iii) The diagonals of a square are always perpendicular to one another.

(iv) All the sides of a rhombus are of equal length.

(v) All the sides of a parallelogram are of equal length.

(vi) The opposite sides of the trapezium are parallel.

(i) True

(ii) True

(iii) True

(iv) True

(v) False

(vi) False

Question 20.

Give reasons for the following:

(i) A square can be thought of as a special rectangle.

(ii) A rectangle can be thought of as a special parallelogram.

(iii) A square can be thought of as a special rhombus.

(iv) Squares, rectangles, and parallelograms are all quadrilaterals.

(v) A square is also a parallelogram.

(i) A square has all the properties of a rectangle. So, it is a special rectangle.

(ii) A rectangle has the same properties as a parallelogram. So, it is a special parallelogram.

(iii) A square has the same properties as that of a rhombus. So, it is a special rhombus.

(iv) Squares, rectangles and parallelograms are all quadrilaterals as they are all enclosed by four sides.

Question 21.

The measure of two angles of a triangle is 720 and 550. Find the measure of the third angle.

Let ∠A,∠B,and ∠C are the three angles of a triangle.

Let the required missing triangle be x∘

∠A+∠B+∠C=180∘(By angle sum property of triangle)

Thus,

72∘+55∘+x∘=180∘

127∘+x∘=180∘

x∘=180∘−127∘

x∘=53∘

Question 22.

Match the following statements :

Measures of Triangle                             Type of Triangle

(i) 3 sides present of equal length                 (a) Scalene

(ii) 2 sides present of equal length                    (b) Isosceles right-angled

(iii) All of the sides are of different length              (c) Obtuse-angled

(iv) 3 acute angles (d) Right-angled

(v) 1 right angle (e) Equilateral

(vi) 1 obtuse angle (f) Acute-angled

(vii) 1 right angle with only two sides of equal length (g) Isosceles

(i) Equilateral (e)

(ii) Isosceles (g)

(iii) Scalene (a)

(iv) Acute-angled (f)

(v) Right-angled (d)

(vi) Obtuse-angled (c)

(vii) Isosceles right-angled (b)

Question 23.

What part of a revolution will you turn through if you stand facing

(i) east and turn clockwise to face north?

(ii) south and turn clockwise to face east?

(iii) west and turn clockwise to face east?

If we revolve one complete round in either clockwise or in an anti-clockwise direction, then we will revolve it by 360º, and the two adjacent directions will be at 90º or 1/4 of a complete revolution away from each other.

(a) If we start facing east and turn clockwise to face north, then we have to make 3/4 of a revolution.​​

(b)  If we start facing south and turn clockwise to face east, then we have to make 3/4 of a revolution.

(c) If we start facing west and turn clockwise to face wast, then we have to make 1/2 of a revolution.

Question 24.

Find the number of right angles that are turned through by the hour hand of a clock when it goes from

(i) 3 to 6 (ii) 2 to 8 (iii) 5 to 11

(iv) 10 to 1 (v) 12 to 9 (vi) 12 to 6

The hour hand of the clock revolves by 360º or four right angles in 1 complete round.

(i) The hour hand of a clock revolves by 90º or one right angle when it goes from 3 to 6.

​​(ii) The hour hand of a clock revolves by 180º or two right angles when it goes from 2 to 8.

(iii) The hour hand of a clock revolves by 180º or two right angles when it goes from 5 to 11.

(iv) The hour hand of a clock revolves by 90º or one right angle when it goes from 10 to 1.

(v) The hour hand of a clock revolves by 270º or three right angles when it goes from 12 to 9.

(vi) The hour hand of a clock revolves by 180º or two right angles when it goes from 12 to 6.

Question 25.

There are only two set squares in your box. What will be the measures of the angles that are formed at their corners? Will they have any angle measure that is common?

One has a measure of 90°, 45°, and 45°.

Others have a measure of 90°, 30°, and 60°.

Therefore, the angle of 90° is common between them.

Question 26.

What shape is

(a) your instrument box? (b) a brick?

(c) a matchbox? (d) a road-roller?

(a) Cuboid

(b) Cuboid

(c) Cuboid

(d) Cylinder

(e) Sphere

Question 27.

Study the diagram. Line l is perpendicular to the line m.

(i) Is CE = EG?

(ii) Does PE bisect CG?

(iii) Identify any two line segments for which PE is the perpendicular bisector.

(iv) Are these true?

(a) AC > FG.

(b) CD = GH.

(c) BC < EH.

(i) Yes. As CE = EG = 2 units

(ii) Yes. PE bisects CG since CE = EG.

(iii) Line DF and BH.

(iv) (a) True. As the length of AC and FG are two units and 1 unit, respectively.

(b) True. Because both of them will have 1 unit length.

(c) True. As the length of BC and EH are 1 unit and three units, respectively.

## Benefits of Solving Class 6 Maths Chapter 5 Extra Questions

Practice is crucial to score better in exams. In Maths, practice is important for various reasons. It helps students clear their doubts and build their basic concepts. Many students fear maths because they don’t get the subject matter. In such cases, they must solve sums to boost their confidence and clear their ideas. The Important Questions Class 6 Maths Chapter 5 will help students build practice habits. There will be other benefits to solving these questions too. They are-

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• The experts have tried to include questions from all over the chapter. They have attempted to incorporate every important concept of this chapter. For this purpose, they have taken help from several sources. Apart from this, they have also included questions from past years’ question papers so that students may know possible types of questions in exams. Thus, Chapter 5 Class 6 Maths Important Questions will help students greatly. It will not help them to practise questions regularly but also boost their preparation for exams. Thus, it will help to bring extra marks in exams.

Extramarks is a leading educational company in India that provides all the study material related to CBSE and NCERT. We understand the needs of students and try to supply study material according to their demands. One may register on our official website of Extramarks and download this material. You will find the CBSE syllabus, CBSE revision notes, CBSE extra questions, NCERT solutions, NCERT Exemplar, NCERT important questions, CBSE past years’ question papers, vital formulas and many more. Like the Important Questions Class 6 Maths Chapter 5, you will also find important questions for other chapters. Some links to study material are given below-

• NCERT books
• Important questions
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• CBSE syllabus
• CBSE sample papers
• CBSE past years’ question papers
• Important formulas
• CBSE extra questions

Q.1 How many faces, edges and vertices does a cuboid have?

2 faces, 4 edges and 6 vertices

4 faces, 6 edges and 6 vertices

5 faces, 10 edges and 8 vertices

6 faces, 12 edges and 8 vertices

Marks:1

Ans

A cuboid is a three dimensional shape which has 6 faces, 12 edges and 8 vertices.

Q.2 A minute hand of a clock starts from 3 and makes an angle of 180° after some time. The minute hand stops at:

(a) 8

(b) 7

(c) 9

(d) 10

Marks:1

Ans(c) 9

If a minute hand of a clock starts from 3 and make an angle of 180°, then it will stop at 9.

Q.3 In which of the following quadrilaterals, the diagonals intersect each other at 90 degrees?
(a) Rhombus

(b) Trapezium

(c) Rectangle

(d) Parallelogram

Marks:1

Ans

(a) Rhombus

Rhombus

In rhombus, the diagonals intersect each other at 90 degrees.

Q.4 Can a triangle have two obtuse angles ?

Marks:1

Ans

No, because the sum of two obtuse angles is more than 180 and this is not possible in the triangle.

Q.5 State true or false : A reflex angle is less than a straight angle.

Marks:1

Ans

False.

A reflex angle is an angle which is more than 180 and less than 360. Also a straight angle is equal to 180°.

Hence, a reflex angle is larger than a straight angle.